Physician Focus: Parkinson's disease is still a mystery

Dr. Anna Hohler and Dr. Samuel Frank

Wednesday

Oct 26, 2011 at 12:01 AMOct 26, 2011 at 1:39 AM

Despite remarkable discoveries and technological advances over the years, medicine still has its mysteries, and Parkinson's disease is among them. Parkinson's is named for the English doctor, James Parkinson, who first identified and described the condition in 1817 in "An Essay on the Shaking Palsy."

Despite remarkable discoveries and technological advances over the years, medicine still has its mysteries, and Parkinson's disease is among them.

A neurological disorder of the brain that affects a person's muscle control and bodily movements, Parkinson's is named for the English doctor, James Parkinson, who first identified and described the condition in 1817 in "An Essay on the Shaking Palsy."

The symptoms and onset of the disease appear slowly and gradually, usually without the patient's knowledge, a fact noted by Dr. Parkinson nearly 200 years ago.

"So slight and nearly imperceptible are the first inroads of this malady," he wrote, "and so extremely slow its progress, that it rarely happens that the patient can form any recollection of the precise period of its commencement."

Nearly 1 million people in the United States suffer from the condition, and its incidence is growing: 50,000 to 60,000 new cases are being diagnosed each year. It is a disorder affecting an older population, usually beginning in people 60 years of age and up.

Parkinson's disease causes tremors or shaking of the face, arms or legs; stiffness in the limbs or trunk; slowness of movement; and poor balance and coordination. It is a chronic condition, persisting over a long time, and it is progressive, with symptoms growing worse over time.

The mystery of Parkinson's is its cause. While the disease is known to be intrinsic to the brain, where degeneration occurs in certain parts of the brain, the specific causes of the condition are unknown. Several theories about causes do exist, including genetic predisposition, environmental exposure –– especially to heavy metals or pesticides –– and traumatic head injury.

This lack of a known cause and the absence of testing to pinpoint the disorder –– there's no blood test, X-ray or other imaging test to diagnose the disease –– make it difficult for physicians to get an accurate diagnosis.

Physicians must look beyond the tremors, stiffness or slow movement and examine how the condition may be affecting aspects of a patient's daily life. Other indications of the disease may include a decrease in animation of the face, or "poker face," slowness of speech, difficulty with handwriting, problems with sleep or issues surrounding mood. Those conditions, along with the tremors and stiffness, combined with an extensive medical history and physical examination, help lead physicians to a proper diagnosis.

One known characteristic of the condition is a dramatic drop in the amount of dopamine in the brain. Dopamine is a neurochemical that sends signals between neurons and helps regulate movement, among other functions. Replacing the dopamine lost over time with medication is part of the treatment for patients with Parkinson's disease. Other medications may be prescribed as well and, in some cases, surgery may be appropriate. This surgery, called deep brain stimulation, involves implanting electrodes into the brain that are then programmed to reduce tremors and slowness of movement.

Although no cure for Parkinson's exists, research continues, particularly for a medication that can slow the progression of the disease. Current therapies are good at treating the symptoms of Parkinson's, but nothing is now available to slow its progression.

The good news is that the medications and therapies available now allow patients to live a full life. In diagnosing and treating patients, physicians approach each person individually, tailoring their medications and treatments. Patients that stay in close contact with their physicians, those that stay with proper medications and have them adjusted if and when necessary, and those that live a healthy lifestyle with proper diet and exercise, can have a good quality of life.

To learn more about Parkinson's, including early warning signs and living with the disease, visit the American Parkinson Disease Association at www.apdaparkinson.org. And for a video discussion, visit www.physicianfocus.org.

Anna Hohler, M.D., and Samuel Frank, M.D., are board-certified neurologists at Boston Medical Center who specialize in treating Parkinson's patients. Physician Focus is a public service of the Massachusetts Medical Society. Readers should use their own judgment when seeking medical care and consult with their physician for treatment. Send comments to PhysicianFocus@mms.org

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